Two North Carolina prison employees were killed and several others hurt after inmates at a sewing plant started a fire in an unsuccessful escape attempt, authorities said.

How the employees were killed at the Pasquotank Correctional Institution in Elizabeth City was not released.

At least 10 people were taken to hospitals after the fire about 3pm on Thursday, Sentara Albemarle Medical Center spokesman Peter Sengenberger said. He did not have a breakdown of whether they were employees or inmates.

Prison spokesman Keith Acree said several employees were hurt.

The inmates started the fire at a Correction Enterprises sewing plant inside prison walls. The plant makes safety vests and embroidered items, Mr Acree said in a statement.

Prison workers did several counts after the fire and all 725 inmates were accounted for.

The prison near the northeast North Carolina coast can house nearly 900 adult, male felons in both high-security and minimum-custody buildings.

The public school district locked doors at three nearby schools after getting word about 3.30pm of the escape attempt.

The notice came as students at one of the facilities, Pasquotank High School, were just to be released for the day and after dismissal times for the elementary and middle schools, said Tammy Sawyer, a spokeswoman for Elizabeth City-Pasquotank Public Schools.

Buses were ordered back to their schools with any students still in transit.

"We didn't want kids home alone or in transport with the potential situation that was unfolding," Ms Sawyer said.

Local emergency management officials said about 5pm it was again safe for students to return home.

The prison has reported other incidents this year. In April, an argument between two inmates at the prison led to one prisoner stabbing the other several times in the upper torso.

Two months earlier, a guard was charged with trying to smuggle illegal drugs, phones and cigarettes behind prison walls.